The invention is related to a process for preparing beadlets containing fat soluble substances.
U.S. Pat. No. 4,670,247 reportedly discloses the preparation of fat soluble beadlets by emulsifying a fat soluble substance selected from the group consisting of vitamin A, D, E, K and derivatives thereof, carotenoids, polyunsaturated fatty acids, the flavoring or aroma substances with water, gelatin and a sugar. The emulsion is then converted to droplets. The droplets are collected in a starchy collecting powder to form particles. The particles from the starchy collecting powder are then heat treated to form a water insoluble beadlet. The selected fat soluble substance is preferably vitamin A acetate or vitamin A palmitate. The sugar is a reducing sugar and can be selected from the group consisting of fructose, glucose, lactose, maltose, xylose, and mixtures thereof. The collecting powder used according to U.S. Pat. No. 4,670,247 is a starchy powder. However, other powders such as, e.g., calcium silicate (EP 0 867 177 A), calcium aluminum silicate, tri-calcium phosphate, silicic acid or celluloses can also be used. The heat treatment results in crosslinking of the gelatin matrix.
According to conventional heating methods, the crosslinking step was performed by heating on preheated stainless steel trays in an electric oven at a temperature of from about 90xc2x0 C. for 2 hours to about 180xc2x0 C. for less than a minute. These conventional crosslinking methods by heating have the disadvantage that the crosslinking is not uniform due to the non-uniformity of the heat treatment. Moreover, the previous processes are often less satisfactory because too much energy is expended in their performance and thus they are uneconomical.
It has now been found that these disadvantages can be overcome when the crosslinking step is performed by exposure to radiation or by using an enzyme.
The present invention relates to a process for preparing beadlets containing fat soluble substances having the steps of:
(1) forming an aqueous emulsion of a fat soluble substance, a gelatin, and a reducing agent and, optionally, an antioxidant and/or a humectant;
(2) optionally adding a crosslinking enzyme;
(3) converting the emulsion into a dry powder; and
(4) crosslinking the gelatin matrix in the coated particles by exposing the coated particles to radiation or, in the case of a crosslinking enzyme being present, by incubating the coated particles.